Lulu Hunt Peters (1873-1930) was an American doctor and author who wrote a featured newspaper column entitled Diet and Health, which she followed up with a best-selling book, Diet & Health: With Key to the Calories. Having grown up a hefty child and once weighing 220 lbs, she was extremely conscious of the problems weight presented to her. Peters' book Diet and Health: With Key to the Calories, targeted specifically to American women, became extremely popular, selling 2 million copies. People found it witty and entertaining. The book was the first dieting book to become a bestseller, and it remained in the top ten non-fiction bestselling books from 1922 to 1926, topping the list for two years running, in 1924 and 1925.
In the book, she explained the concept of the calorie as a scientific unit of measurement of the energy potentially available from food. The concept of the calorie was so new that her book even provides instruction on the word's pronunciation. She explains the importance of balancing food intake and energy used, and suggests a number of exercises, supported with simple cartoons.